1. How frequent are biotic worlds? The Impact of Kepler on the likelihood of Extra-terrestrial Life Amri Wandel - Hebrew Univ. of Jerusalem

2. ILASOL 2012 A. Wandel How frequent are terrestrial exo-planets?  Do other stars have planets?  If so, are they Earthlike?  Are they in the Habitable zone?  The exo-planet boom  What has changed with Kepler? 2

3. ILASOL 2012 A. Wandel Star types suitable for the evolution of life  Too big(M>1.5Mo)- Main Sequence lifetime insufficient for the evolution of life  Too small (< 0.5 Mo) - eruptive (planetary temperature instable)  This leaves ~ 10% of all stars. 3

4. עוברי כוכבים ו ” מערכות שמש ” בערפילית אוריון עוברי כוכבים ו ” מערכות שמש ” בערפילית אוריון Planetary disks being born in Orion

5. 5 ILASOL 2012 A. Wandel The Doppler method V * ~m p a p -1/2 51 Peg V * ~m p a p -1/2 51 Peg

6. 6 ILASOL 2012 A. Wandel Doppler method is biased towards massive,near planets

7. Observatories in Space SIM Kepler Darwin CoRoT 7 ILASOL 2012 A. Wandel

8. The transit method The inclination must be very close to 90° 8 ILASOL 2012 A. Wandel

9. HD209458 HD209458 Planet mass Planet radius Planet density 9 ILASOL 2012 A. Wandel

10. Sensitivity of exo-planet projects  Radial velocity (Doppler)  Transit  Micro-lensing 10 ILASOL 2012 A. Wandel

11. The Kepler mission Search Earthlike exo-planets 11 ILASOL 2012 A. Wandel

12. Kepler’s first planets

14. The Habitable Zone

15. ILASOL 2012 A. Wandel How many biotic woldss exist in the Galaxy ? 15 10 11 stars 10% Sunlike Planets in HZ Earthlike n HZ ? ? Kepler 22b 5.12.2011 Kepler 20e,f 19.12.2011

16. ILASOL 2012 A. Wandel How frequent is extra-terrestrial life? 16

17. ILASOL 2009 Amri Wandel Probability for a terrestrial planet to become biotic vs. cosmic time Earth probability Time (bill.yrs) 17

18. Probabilities for terrestrial planets and biotic worlds 18 Average distance to nearest biotic exoplanet: D b ~10 ly (F p F b ) -1/3 Let’s assume two extreme scenarios: Optimistic: F p =1, F b =1, D b ~10 ly Pessimistic: F p =0.01, F b =0.001 D b ~500 ly

19. Exo-Planets by Micro-lensing 19 ILASOL 2012 A. Wandel

20. Distance to nearest biotic planet 20 11+Log (FpFb)

21. ILASOL 2012 A. Wandel Probability for a biotic planet within 100 ly 21 11+Log (FpFb)

22. Seems to be much more likely After Kepler extra-terrestrial life